During wireless network transmission, there are unicast transmission and broadcast multicast transmission. A multimedia broadcast multicast service (MBMS) transmission mode is one of broadcast multicast transmission. In this transmission mode, multiple cells send data to multiple user equipments (UE) by using a data transmission method of a single frequency network (SFN). In this case, a subframe needs to be reserved to transmit MBMS data.
Data corresponding to an MBMS is transmitted by an MBMS control node at a network side to all base stations in a multicast/broadcast single frequency network (MBSFN) area corresponding to the MBMS data, and then is sent by these base stations to UE in an MBSFN manner. An MBSFN reference signal (MBSFN RS) is used to perform MBMS related measurement and demodulate the MBMS data.
In an MBMS communications system, congestion may occur at a network side, or MBMS data is interrupted due to some reasons, that is, a base station does not receive the MBMS data sent by a node at the network side. In this case, a reserved subframe can only be idle. As a result, resource usage is low.